Coatings and paints are routinely used to beautify and protect substrates. The most simple coatings and paints are made of a polymer (the binder) in a solvent (the vehicle), which is commonly called a lacquer. Paints and coatings modify the appearance of an object by adding color, gloss, or texture, and by blending with or differentiating from a surrounding environment. For example, a surface that is highly light scattering (i.e. a flat surface) can be made glossy by the application of a paint that has a high gloss. Conversely, a glossy surface can be made to appear flat. Thus, the painted surface is hidden, altered, and ultimately changed in some manner by the presence of the coating. In addition, paints also protect the surface from the surrounding elements and prevent or reduce the corrosive process.
Although paints and coatings alter the appearance of the surface, the coating itself can get dirty. The dirt can dull the coating by increasing the light scattering or modifying the color. Many attempts to create organic coatings that resist dirt and contamination have been undertaken. In one case, hydrophobic coatings with a low surface energy that resist water and, thus, are resistant to dirt have been created. For example, highly fluorinated polymers related to Teflon have been used for this purpose. These coatings often have a surface energy of no more than 15 dynes, which results in water forming beads on the surface rather than wetting the surface. Generally, these coatings take more time to become contaminated and maintain the appearance of the object longer, but they still eventually need to be cleaned. Thus, it is desirable to have coatings with hydrophilic surface with self-cleaning properties.
Low temperatures, in some cases, may affect the durability of paints due to frost. Frost formation occurs when water vapor in the surrounding air comes into contact with cold surfaces through heat and mass transfer. Frost is undesirable as repeated freeze-thawing cycles may easily damage the organic binder present in the coating. A few studies have shown that changing the surface energy of the coatings, such as increasing the surface hydrophilicity or hydrophobicity, has significant effects on the frost deposition process, particularly in the first frost cycle. Accordingly, there is a need to develop coatings with hydrophilic and anti-freeze properties.